Thursday, April 16, 2015

This Post be Dammed!

DES MOINES — For the better part of a century, submerged dams were workhorses of the American heartland, harnessing the power of rivers to run grain mills, generate electricity, and keep lakes and ponds full of water as a hedge against drought.

These walls of concrete, called low-head dams for their minimal profile, outlasted their original purpose long ago. Today, they are better known for creating the type of wide, smooth waterway that invites city planners to turn an urban river into rustic recreational space.

But beneath the seemingly gentle cascades and quiet rumble, the dams hide a sinister secret: They have dragged hundreds of unsuspecting swimmers and boaters into their churning waters and drowned them, sometimes within sight of busy sidewalks and cafes.

‘‘The builders of these dams have created a very elegant trap for human beings,’’ said Nate Hoogeveen, who heads river programs for the Iowa Department of Natural Resources. ‘‘Once people go over the dam, it’s impossible to climb out.’’

Now a spike in deaths is inciting a debate about whether the dams should be ripped out, even if it means letting scenic river banks turn to mud.

Since the 1950s, at least 441 people have died at 235 low-head dams in 38 states, according to researchers at Brigham Young University. More than one-third of the deaths have occurred in Iowa, Minnesota, and Pennsylvania. Other top states for low-head dam deaths include Illinois, California, Maryland, Ohio, Texas, and Virginia.

About half of those deaths occurred in the past 15 years — a period when many cities have sought to repurpose their rivers into picturesque attractions that would draw tourists and shoppers to business districts. Many rivers once used mostly by fishermen are now teeming with kayakers and rowing teams and used as the site for summer festivals.

The dams, typically built in the early 1900s, can look harmless, especially from upriver. An approaching boater or swimmer often sees nothing more menacing than a gentle drop, perhaps as little as 4 or 5 feet.

But once they fall into the roiling water below, people find themselves pounded by a never-ending wave of water that forces them to the bottom. If they can bob to the surface, the recirculating current carries them back to the face of the dam; the nightmare repeats.

Experts say the number of dead is undoubtedly higher than the confirmed cases. No government agency tracks deaths, and it is unclear how many such dams exist. Estimates go from 3,000 to 5,000.

On the Des Moines River, two low-head dams are at both ends of a stretch of the channel that runs through downtown Des Moines. At least 15 people have died there.

It’s unclear what’s behind the increased deaths in recent years, but Bruce Tschantz, a Knoxville, Tenn., hydraulic engineer who has become an expert on the dams, believes that it is a combination of people spending more time on rivers and not understanding the power of the churning water.

Making matters worse: Many of the dams are poorly marked and lack lines or buoys for imperiled boaters or swimmers to grasp.

Millions of older people are getting tests they don’t need to prove they are healthy enough to have cataracts removed, a new study finds. The excess testing before this quick, safe eye procedure is costing them and Medicare a bundle, and many patients don’t know they can question it, doctors say.

‘‘They should ask, ‘Is it really necessary?’ ’’ and how much it will cost them in co-insurance — usually 20 percent under Medicare, said one study leader, Dr. R. Adams Dudley of the University of California San Francisco.

It’s amazing ‘‘how much harm a doctor can do with the wiggle of their pen or a check in a box’’ to order these tests, he said.

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Removing cataracts, which cloud vision, is the most common elective operation for older adults, done 1.7 million times each year in the United States. The outpatient procedure takes about 18 minutes and requires only numbing eye drops, not general anesthesia.

‘‘This is one of the lowest-risk surgery procedures you can have,’’ with less than a 1 percent risk of major heart problems or death, said Dr. Catherine Lee Chen, a UCSF anesthesiologist who led the study.

Yet many doctors order preoperative tests such as blood work, chest X-rays, electrocardiograms, and even advanced heart and lung tests to ensure a patient can withstand the procedure.

Major studies found that about half of Medicare recipients were getting such tests before cataract removal and that routine testing did not improve outcomes or safety. In 2002, several medical groups issued guidelines advising against it.

Chen did the study to determine whether the situation had improved and found it had not.I can't $ee why, can you?

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The results are surprising, said Ellen Meara, a professor at the Dartmouth Institute for Health Policy and Clinical Practice.

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